Spain have confirmed David De Gea has suffered an injury and are monitoring the goalkeeper "day-to-day" in a bid to get him fit for the rest of their World Cup campaign.

Rumours surfaced on Sunday that Manchester United goalkeeper De Gea was carrying an injury and could be ruled out for the rest of the group stage. Holders Spain were thrashed 5-1 by the Netherlands in their opening Group B encounter in Salvador.

A statement released by the Royal Spanish Football Federation (RFEF) said: "After undergoing tests, it was decided that David de Gea would not take part in the team's afternoon training session owing to muscle discomfort in the gluteal region.

"The Spanish national team's medical services will evaluate day-by-day the goalkeeper's recovery to determine his reincorporation into the group."

Casillas failed to meet a cross for the third goal before gifting Robin van Persie his second of the night during Friday's match. His position has since been questioned by some sections of the Spanish media, with De Gea and Pepe Reina tipped to replace him for Wednesday's crunch clash against Chile.

Spain then close out their group campaign against Australia, who suffered a 3-1 loss to Chile in their opening fixture, on June 23.